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We report on the characterization and first laser operation of ceramic Yb:LuScO3 in a thin-disk oscillator. The optical performance achieved with a ceramic Yb:LuScO3 disk is compared to the one obtained with an existing ceramic Yb:Lu2O3 disk for reference. The characterization covers the measurement of the fluorescence spectra, the fluorescence lifetimes, and nomarsky imaging. The investigation on the laser operation covers the measurement of resonator losses, output powers, and thermal behavior during continuous-wave operation in a multimode thin-disk oscillator. An average output power of 149 W and a slope efficiency of 51.8% were achieved with the ceramic Yb:LuScO3 disk which reached a maximum surface temperature of about 150 °C. At the same temperature level, a disk made of the already established ceramic Yb:Lu2O3 delivered 957 W of output power with a slope efficiency of 75.7%. [ABSTRACT FROM AUTHOR]

Trans-laminar fracture is an important topic for engineering composites. In this study, trans-laminar fracture initiation in quasi-isotropic carbon/epoxy laminates made of non-crimp fabrics was examined using in situ fast synchrotron X-ray radiography and ex situ X-ray computed tomography. The maximum split lengths were measured by in situ radiography and were compared with the predicted values in a detailed FE model using cohesive elements. Ex situ computed tomography scans were also conducted to confirm that no fibre breakage occurs before the final load drop in the experiments. In situ and ex situ observations are complementary for the understanding of damage initiation. [ABSTRACT FROM AUTHOR]

Reinforcement learning (RL) has achieved remarkable advancements in navigation tasks in recent years. However, tackling multi-goal navigation tasks with sparse rewards remains a complex and challenging problem due to the long-sequence decision-making involved. Such multi-goal navigation tasks inherently incorporate a hybrid action space, where the robot needs to select a navigation endpoint first before executing primitive actions. To address the problem of multi-goal navigation with sparse rewards, we introduce a novel hierarchical RL framework named Hierarchical RL with Multi-Goal (HRL-MG). The main idea of HRL-MG is to divide and conquer the hybrid action space, splitting long-sequence decisions into short-sequence decisions. The HRL-MG framework is composed of two main modules: a selector and an actuator. The selector employs a temporal abstraction hierarchical architecture designed to specify a desired end goal based on the discrete action space. Conversely, the actuator utilizes a continuous goal-oriented hierarchical architecture developed to enact continuous action sequences to reach the desired end goal specified by the selector. In addition, we incorporate a dynamic goal detection mechanism, grounded in hindsight experience replay, to mitigate the challenges posed by sparse reward landscapes. We validated the algorithm’s efficacy on both the discrete environment Maze_2D and the continuous robotic environment MuJoCo ‘Ant’. The results indicate that HRL-MG significantly outperforms other methods in multi-goal navigation tasks with sparse rewards. [ABSTRACT FROM AUTHOR]

In this article, a robust fault-tolerant sliding mode controller is proposed for a class of non-homogeneous Euler–Bernoulli beams which contains controller time-varying fault, external unknown spatiotemporally varying disturbance, and parametric uncertainties. Furthermore, to reduce the number of correspondence between the controller and the actuator, two event-triggered mechanisms are incorporated into the controller design. The sliding surface designed ensures that the system is uniformly ultimately bounded and robust to the parameter uncertainties in model. In addition, the Euler–Bernoulli beam can be used as a model for the flexible wind turbine tower. Numerical simulations are shown to illustrate the validity and effectiveness of the proposed control method. The simulation results show that in the presence of unknown faults and parametric uncertainties, the proposed controller can still effectively suppress the vibration of the tower, while the event-triggered mechanism significantly reduces the communications burden. [ABSTRACT FROM AUTHOR]

In type-II Weyl semimetals (WSMs), the tilting of the Weyl cones leads to the coexistence of electron and hole pockets that touch at the Weyl nodes. These electrons and holes experience the Berry curvature generated by the Weyl nodes, leading to an anomalous Hall effect that is highly sensitive to the Fermi level position. Here we have identified field-induced ferromagnetic MnBi2-xSbxTe4 as an ideal type-II WSM with a single pair of Weyl nodes. By employing a combination of quantum oscillations and high-field Hall measurements, we have resolved the evolution of Fermi-surface sections as the Fermi level is tuned across the charge neutrality point, precisely matching the band structure of an ideal type-II WSM. Furthermore, the anomalous Hall conductivity exhibits a heartbeat-like behavior as the Fermi level is tuned across the Weyl nodes, a feature of type-II WSMs that was long predicted by theory. Our work uncovers a large free carrier contribution to the anomalous Hall effect resulting from the unique interplay between the Fermi surface and diverging Berry curvature in magnetic type-II WSMs.The authors study the field-induced ferromagnetic state of MnBi2-xSbxTe4 by quantum oscillations and high-field Hall effect measurements. They confirm a single pair of type-II Weyl nodes, the long-sought “ideal” Weyl semimetal. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Phase-pure two-dimensional Fe_xGeTe_2 magnets with near-room temperature T_C" published in the journal Nano Research. The correction is related to the author affiliations listed in the article. The corrected list of authors includes Govindan Kutty Rajendran Nair, Zhaowei Zhang, Fuchen Hou, Ali Abdelaziem, Xiaodong Xu, Steve Wu Qing Yang, Nan Zhang, Weiqi Li, Chao Zhu, Yao Wu, Heng Weiling, Lixing Kang, Teddy Salim, Jiadong Zhou, Lin Ke, Junhao Lin, Xingji Li, Weibo Gao, and Zheng Liu. The correction notice provides the correct author affiliations and contact information for Xingji Li, Weibo Gao, and Zheng Liu. The article was published in 2024 and can be accessed using the provided DOI. [Extracted from the article]

We report on the characterization and first laser operation of ceramic Yb:LuScO3 in a thin-disk oscillator. The optical performance achieved with a ceramic Yb:LuScO3 disk is compared to the one obtained with an existing ceramic Yb:Lu2O3 disk for reference. The characterization covers the measurement of the fluorescence spectra, the fluorescence lifetimes, and nomarsky imaging. The investigation on the laser operation covers the measurement of resonator losses, output powers, and thermal behavior during continuous-wave operation in a multimode thin-disk oscillator. An average output power of 149 W and a slope efficiency of 51.8% were achieved with the ceramic Yb:LuScO3 disk which reached a maximum surface temperature of about 150 °C. At the same temperature level, a disk made of the already established ceramic Yb:Lu2O3 delivered 957 W of output power with a slope efficiency of 75.7%. [ABSTRACT FROM AUTHOR]

This correction notice is for an article titled "Hyperbolic exciton polaritons in a van der Waals magnet" published in Nature Communications. The correction addresses an error in the reference list order, where references 47 and 48 were switched with references 49 and 50. The correction has been made in both the PDF and HTML versions of the article. The authors who contributed equally to the article are Francesco L. Ruta, Shuai Zhang, and Yinming Shao, along with several other authors listed in the correction notice. [Extracted from the article]

The study investigates the role of digital-government (DG), government utilization, and regional integration on public health services (PHS) by considering E-government and globalization. This study takes public services fragility as a proxy for public health services. In contrast, E-government development as a DG globalization index (GI) has been taken as a proxy of regional integration, and government expenditures (GE) as a fiscal state capacity. The study employed a two-step system generalized method of moments estimation for the sample of 45-panel Asian economies from 2006-to-2022. The results reveal that DG substantially impacted and improved the PHS in Asian economies in the past decade. Moreover, regional integration added fuel to this progression and substantially influenced the PHS. However, GE adversely affects the PHS due to lousy governance and leakage of target spending. Furthermore, the novel DG integration with GE and GI promoted PHS and reduced health fragility through better resource utilization and technology deployment. It also reveals that DG helps in reducing the loopholes of GE and makes the resource implementation transparent and effective, which impacts the PHS. It concludes that these interactions with public policies play a prominent role in comprehensive coverage and healthcare accessibility in Asia through technology deployment with prudent administration strategies. It’s a novel study that integrates digitalization with regional integration and government expenditures from an Asian perspective by considering PHS, which made this study helpful for policy drafting during the COVID-19 pandemic and proposed a better framework to deal with future calamities. [ABSTRACT FROM AUTHOR]